This invention relates in general to the construction of safety helmets and in particular to a new and useful device adapted to be associated with the safety helmet for the closing of the narices.
The invention relates to a protective cap with closure elements serving to close the narices, which closure elements are arranged on a support present inside the protective cap and are connected with devices for the transmission of force of an operating element received from the outside of the protective cap.
A similar protective cap is known from German OS No. 28 53 213.
Protective caps of this kind are used in respirators, in diving, for the flight personnel in aviation, and generally wherever the facial or head area must be protected from access of nonbreathable gases or where respiration is to be made possible by suitable aids.
In the known protective cap, there is a support in the form of a half-mask, at which a lever is pivotably passed through each side of the nose region of the cap and which includes a roll drum fastened to the end of each lever. On the outside the levers are joined by an operating strap. In an inoperative position the strap rests, flapped down, against the cap, the drums standing erect in the interior. As the straps are flapped up, the drums roll down on the inner mask on both sides of the nose portion and compress the narices by way of the mask.
Such a device for closing the narices is meaningful when the wearer of the protective cap must overcome great differences in altitude within short periods. This is the case when, for example, divers must go down to great depths. It is very useful to pilots who fly at high altitudes and are supplied with oxygen through a mask. At an extreme rate of drop, the pilot must provide for pressure equalization between his surrounding and the inner auditory canal. Some of the pilots can achieve this pressure compensation by swallowing or by movement of the lower jaw. Others can bring such a pressure equalization about only by a pressure variation in the nose-throat region with the nose closed. Such a manipulation is called in technical language "Valsalva's maneuver". Preferably it should be possible to be carried out by the pilot without alteration at the protective cap from the outside. In the known device it is found to be disadvantageous that the pilot must, to carry out this manipulation, move his arm into the field of vision of the protective cap, whereby his field of sight is greatly restricted at least for a short period, but which cannot be neglected at the high flight velocities. In addition, the strap must be left in flapped-up position until the pressure equalization is carried out. During this time the strap hinders the pilot in the free view through the viewing pane onto his flight instruments.
Another device for the execution of the "Valsalva maneuver" is known from GB-A-20 47 545. In it are shown two pressure pieces attached under spring load in the mask, which are connected by a flexible band passing under the nose. During the upward displacement of the mask, the band applies against the nose and pulls the pressure pieces together laterally. The required pivoting of the cap and mask is complicated, impairs the tight seal, and interferes with the vision at crucial moments. Moreover, the parts projecting into the mask space are a hinderance in wearing the mask.